All sub-60 raw materials are a gamble. Remember, lowbies will be able to log onto their herbalist alts and fly around at 310% to farm the herbs themselves if they need to. Same applies for all ores and herbs. Outland and WotLK ores/herbs is where you should invest.
In my opinion, people who will fly around on their mains to get materials for their new alts are not your customers, and never were except for 1-2 exceptions. These people don't value their time highly (because earning at higher levels is almost always higher than at lower levels).
And why should Outland / Northrend be better? According to the logic, they can already go gather stuff from there NOW.
In effect, customers for low-level/profession leveling materials are people who want something NOW and don't care too much about the price because they sit on 50k gold anyway. These people don't want to fly around for some hours just to level their newest char's profession when they could just plop down 500g to get the same materials directly.